On The Clock: Daylight Saving Time Has Roots in World War I

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A historic street clock near the Fifth Avenue Building stands in Manhattan as Americans prepare to move their clocks forward for the start of daylight saving time, a tradition that began during World War I. (Darius Radzius)

Twice a year, Americans reset their clocks and lose an hour of sleep. The tradition may feel like a modern nuisance, but it began as a wartime policy during World War I.

At 2 a.m. local time Sunday, March 8, most Americans moved their clocks forward one hour as Daylight Saving Time (DST) begun for 2026.

The policy first took hold during World War I as part of a national effort to conserve fuel and electricity for the war. Lawmakers believed shifting daylight later into the evening would reduce the need for artificial lighting and free up energy for factories, transportation and military operations.

Nineteen states have passed laws or resolutions supporting permanent DST, but those changes cannot take effect unless Congress authorizes the shift.

Military.com reached out to the U.S. Department of Transportation, the National Institute of Standards and Technology, the U.S. Naval Observatory and sleep research organizations for comment and background on the policy and its modern impact.

When War Changed Time

More than a century later, the twice-yearly clock change remains a fixture of American life and a regular source of debate.

The United States first adopted DST in 1918 through the Standard Time Act during World War I. Lawmakers hoped shifting daylight later into the evening would conserve fuel and electricity needed for factories and military operations.

The policy sparked backlash almost immediately. Congress repealed it in 1919 after the war ended.

The DoD time reference, the U.S. Naval Observatory Master Clock, is backed up by the Alternate Master Clock pictured here at Schriever Space Force Base, Colorado, Oct. 27, 2023. The Master Clock in Washington, D.C. and the Alternate Master Clock at Schriever SFB are both disciplined to a timescale compromised of signals from multiple atomic clocks. Most users receive this time through the Global Positioning System. (U.S. Space Force photo by Airman 1st Class Justin Todd)

It returned during World War II, when the federal government imposed year-round daylight saving time known as “War Time.”

For decades afterward, communities across the country adopted their own schedules, creating confusion for travelers, broadcasters and businesses.

Congress eventually stepped in. The Uniform Time Act of 1966 established a national system for when most Americans change their clocks.

Today, the U.S. Department of Transportation oversees the nation’s time zones and the uniform observance of daylight saving time. The official U.S. time standard is maintained by the U.S. Naval Observatory and the National Institute of Standards and Technology.

The law allows states to opt out of daylight saving time. Hawaii and most of Arizona do not observe the seasonal clock change.

Lawmakers from both parties have repeatedly proposed ending the twice-yearly clock changes altogether, but Congress has yet to agree on whether the country should remain on standard time or daylight saving time year-round.

The Farmer Story Isn’t True

One of the most persistent myths about DST is that it was created to help farmers.

In reality, many agricultural groups opposed the practice from the beginning. Farm work follows the sun, not the clock.

When the U.S. adopted daylight saving time in 1918 during World War I, farmers complained the policy disrupted routines tied to daylight, including milking schedules and transporting crops to market.

Soybeans are harvested on the Warpup Farm in Warren, Ind., Wednesday, Sept. 17, 2025. (AP Photo/Michael Conroy)

Dairy farmers in particular argued cows could not simply adjust their milking cycles to match a government-mandated clock change.

Agricultural groups and rural lawmakers pushed back quickly. Congress repealed the national daylight saving law in 1919.

Historians say the real drivers were wartime energy concerns and industrial leaders who believed longer evening daylight would reduce electricity demand and increase productivity in factories supporting the war effort.

The idea was simple: more evening daylight meant less artificial lighting and lower energy use.

Even today, many Americans misunderstand the origins of DST. The farming explanation continues to circulate despite historical evidence showing the policy grew out of wartime energy conservation and industrial priorities.

Still Fighting the Clock

Public opinion on the twice-yearly clock change remains divided, but surveys show many Americans would prefer ending the practice.

An October 2025 Associated Press–NORC poll found about 12% of U.S. adults support keeping the current system of changing clocks twice a year. About 47% oppose it, while roughly 40% say they neither favor nor oppose the practice.

A historic street clock near Madison Square Park and the Metropolitan Life Tower in Manhattan as Americans prepare to move their clocks forward for the start of daylight saving time, a policy first adopted in the United States during World War I. (Darius Radzius)

Among Americans who want to end the time switch, opinions differ on what should replace it.

The same survey found about 56% favor permanent DST, which would keep later sunsets year-round. About 42% prefer permanent standard time.

Sleep researchers have increasingly weighed in on the debate. The American Academy of Sleep Medicine said permanent standard time better aligns with human circadian biology and may reduce disruptions to sleep.

Military training experts also emphasize that consistent sleep schedules and exposure to natural light help regulate the body’s internal clock and improve physical performance and recovery.

Other guidance highlights that sunlight exposure early in the day can help regulate circadian rhythms and support better sleep cycles—a factor that researchers say affects alertness and readiness.

Military leaders have also examined fatigue and sleep patterns as part of readiness initiatives, studying how better sleep management and circadian alignment can reduce mistakes and improve operational performance.

For some Americans, the extra evening daylight makes the spring adjustment worthwhile.

Eric Eckelman, speaking with Military.com in New York City, said the longer days make it easier to spend time outdoors after work.

“It’s a little easier to take the dog for a walk,” Eckelman said. “I’ve got a 12-year-old kid who can go out and play basketball.”

Others say the clock change simply feels outdated.

“I don’t see a point sometimes,” Alejandro Rose told Military.com in New York City, adding that he prefers the longer daylight hours that arrive with the spring shift.

Anaise, another New York City resident who spoke with Military.com, said longer daylight hours can influence people’s mood during darker winter months. “I’ve been taking vitamin D consistently, and I feel like my mood has stabilized,” she said.

Jada Patterson, who also spoke with Military.com in New York City, said the spring shift brings mixed feelings.

“It gets lighter later,” she said. “But you lose sleep.”

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